Etjsible link



J. H. NICDOWELL.

FuslL LINK.

APPLICATION FILED NOV. I3, 191?.

Patented Sept. 30, 1919.

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r Y, 4 ONMNSNS l FAITES H. MCDOWELL, OF BROOKLYN, NEW YORK.

FUSIBLE LINK.

Specification of Letters Patent. Patented Sept. 30', 1919.

Application filed November 13, 1917. Serial No. 201,729.A

To all whom t may concern:

Be it known that I, JAMES H. liioDownLL, a citizen of the United States, residing in the city of N ew York, borough of Brooklyn, county of Kings, and State of New York, have invented a certain new and useful Fusible Link, of which the following is a specification.

This invention is a fusible link adapted for use with automatic sprinklers, fireproof windows, and in any other environment where fusible links are generally employed.

Fusible links have long been known and, in almost every case, .embody two or more opposed tension members with an intermediate key-piece. ln the majority of links heretofore employed two tension members are used, each of which is provided with a tapered pocket formed in the inner face of each of said tension members and so positioned therein that, when the complementary tension members are placedin lapped relation, the two pockets will together form a chamber which houses a key-piece having fiat sides which abut the ends of the chamber. The parts are held together by fusible solder. The key-piece, which is in the nature of a strut, lies within the chamber in a position diagonally through the medial line of the length, as viewed from the longitudinal edge thereof, and this position of the parts is maintained until the fusible solder is melted through the currents of local excessive heat, at which time the solder will no longer hold the parts of the tension members in face abutting relation but will allow them to separate under a pull in opposite directions on the respective tension members. In order that the links may move relative to one another longitudinally, it is generally necessary that the key-piece be tilted while its oppositeends remain either seated in the base of the depressions or in lcontact withv the edges formed by the intersection of the depressions with the inner faces of the tension members. This tilting of the key-piece forces the tension members apart, disrupting the fusible solder, and separating the parts of the link.l

In links fof the character described, which is `that quite commonly used, a relatively wide separation between the tension members'is .required before the parts of the link are entirely disassembled. During this operation the opposite edges of the strut remain in contact with the same points of the tension members. This is due to the fact that the operation of the link is dependent upon the tilting of a strut to a position substantially at right angles to the medial line of the link or its opposite ends, or maintained in substantial fixed position relative to the respective tension members. This wide separation of the parts is objectionable, particularly if the device is used to control a sprinkler so that, when these devices have been heretofore employed with sprinklers, the struts have been made exceedingly small and did not possess the great strength which was otherwise obtainable in this form of link. For the reasons given, other forms of fusible link have generally been used in sprinkler control. For example, those forms of link wherein a transversely extending, cylindrical strut or a ball is employed as a key-piece. Such links, while requiring but a very small separation of the parts, do not possess the strength of the link wherein the relatively Hat surfaces of the key-piece come into engagement with the relatively flat surfaces of the tension members as is the case with the strut links referred to. y Y

With the foregoing considerations in mind, the obj ect of the-present invention is to combine in a single link all the advantages of both forms of link referred to without including their disadvantages; that is to say, to provide a strong and reliable link which will be quick in opening and yet not require great separation between the tension members before becoming entirely disrupted.

These features .are obtained in the link of this invention by so constructing the keypiece and tension members that, during the disrupting action of the link, there are numcrousforces at work. F or example, the pressure ofthe tension membersl upon the relatively iat surfaces formed in the key-piece on diametrically opposite sides ofthe axis of rotation thereof causes a rotation of the link on its transverse axis, and, by the action of such rotation, the tension members are positively forced apart and separatedby the edges of said key-piece which engage with the inner faces of the tension members. There are thus certain forces operating to rotate the key-piece into a position to allow the tension members to slip by one another by longitudinal movement and other forces acting to separate or force the tension members apart. The tension members have no bearing on any particular points or portions of the key-piece, as heretofore, but the points of engagement are constantly vary-V ing, thus producing a very active structure when operated, which results ina quick opening 'link and, at the same time, avery strong link inthe absence of disrupting heat.

Features of the invention, other than those specified, will be apparent from the hereinafterdetailed description, read in conjunction with the accompanying drawings.

. key-piece.

Fig. 2 is fa modified form lof link embodying` the same invention but having a keypiece in the form of a globular section.

Fig. 3 is a central, longitudinal section through the link of Fig. 1 showing the `parts in assembled relation. I

Fig. 4 is a similar view of the structure of Fig. 2. s

Fig. 5 'is a greatly enlarged view ofy the structure Vshown in Figs. 2 a'fd 4, showing a portion of the link at the time of opening or disrupting.

Fig. 6 is a detail perspective of the keypiece shown -in Figs. ,1 and 3, and

Fig. 7 -is a ydetail side elevation of the key-piece of Figs. 2 and 4.

In the 4form of the invention illustrated in Figs. l, 3 and 6 the same embodies two tension members A and A. Flach tension member is provided at its opposite endwith apertures a land a, respectively, through which a cab-le or hook may be passed Vfor including the fusible'link in a chain or associatinl it with Vany other form of mechanis'm which it is to control. The tension members A A may be of any desired shape which may vary in accordance with the environment in which the link is adpted to be employed. The shape is of no consequence,

. the invention being directed, more particularly, 'to the formation of the key-piece B of the link. and the pockets or depresisons .r formed 'in the tension members for the reface, with a transverse depression or pocket d, in tension member A, and d in tension member A, and the key-piece B extends into said depressions and is housed thereby.

' The key-piece, instead of being rectangular in cross' section as has generally heretofore been the case, is rabbeted or groovedvon its opposite faces to provide substantially parallel faces e e, and substantially parallel faces 7"' f. In order that the relationship of these faces may be clearly understood the medial planev of the link is shown in dotted lines in certain figures and is designated c, while a plane c is shown which is perpendicular to the plane c. and 4passes through the center of the key-piece. The key-piece is positioned intermediate the members A A in transverse position, and

.the depressions Z and d are shaped in conformity with the contour of said 'key-piece, as sliownin Fig. 1. It will vbe noted that, when in this position, the facer: abuts the inner face of memberA,'while face c abuts the inner face of member A and, as the faces of said members are spaced apart by the fusible solder b, the faces e and e are accordingly spaced a short distance from each side of the-medial plane c, asshown best in Fig. 6, so that they are, in effect, offset' a'short distance though lying in'planes parallel to one another. This formation of the key-piece facilitates the assembling of the link and assures the proper distance between the tension members.

The faces f and f, which are adapted to i' abut with faces Z2 and cl3 of the depressions Z and cZ, respectively, are preferably parallel and preferably make an angle greater than ninety degrees with .the faces e and c so that said faces 7 and f are sloping with respect to the plane c although, if desired,

said faces f and f Y.may coincide with' thev plane c. The .advantage -of having the faces e and e oif-setand the facesv f and f slopingis that the link cannot lact upon dead centers as there will always bea tendency, if thesolder is released, to roll the key-piece about the line of intersection of the planes 0 and c". Thus, while the faces e and c may be in alinement, it is preferable that they be off-set, as described, and

the faces f and f sloping.

In' the construction of Figs. il and 3 the key-piece B is shown as extending the entire width of the link -but,'inpractice,` it may be of lesser length and positioned in pockets intermediate `the edgesoffthe link so that said pockets do not kextend to said edges. The key-piece B -may thus be made in the shape shown in cross section in Fig. 6 but of lesser length or, 'su ch' modified form may partake ,of fthe configuration shown in Figs. 2,V 4 and '7 where vthekeypiece is shown as of spherical contour. In the modified form shown insaid first mentioned figures a sphere VB is provided with the cut faces e and e and the other cutv faces f and f corresponding to the similarly same and, in order that it may be clearly understood, attention is directed to Fig. 5l

which shows thejlinkin the operation of disrupting The construction of Figs. 2, 4, and 7 is shown in Fig. 5 but it will be understood 'that the same modus operandi applies equally well to the preferred form first described. To obviate prolixity, the same reference numerals as applied to the construction of Figs. 1, 3 and 6 will be a plied to Fig. 5 with the exception that t ey sphere will be designated B as in Figs.

,4: and 7. In this connection it will be apparent from the drawings that the tension members yof the modified embodiment are Y formed the same as the tension members of Fig. l with the exception that the depressions inwhich the sphere is seated are, of course, shaped to conform with the contour of said sphere after the same manner as the depressions l and CZ are shaped to conform to the key-piece shown in Fig. 6. It will be assumed, with reference'to Fig. 5, that the link included in a chain or` other tension element, as is generally the case, is impelled by a force upon the tension member A in the direction of the double arrow shown at its upper end, while a similar force is exerted upon the member A in the direction of the double arrows shown at its lower end. These forces tend to slide the members longitudinally of one another, respectively, in the direction of the double arrows.

As long as the solder unites the parts they partake of the position shown in Fig. 4C with the face d2 of the tension members A pulling against the face f of the keypiece, and the face d2 of thetension member A pulling against face 7 of said keypiece, the key-piece, in this manner, counteracting the opposing forces to move the tension members longitudinally. Assuming, however, as the solder becomes f melted or sufficient-ly softened so that it no longer can overcome the tendency of the members A and A to separate, thev forces for separating said tension members are bought into operation with the result shown rin Fig. 5. It will appear that the edge g of pocket l will be pulled upwardly by the force designated by the double arrows at the top of member A, while the edge g will be correspondingly pulled in the opposite direction. These forces will be transmitted to the` key-piece B as next to be described. The edge g will press against the face f, as shown by the arrow g2, and the edge g will press against the face y, as shown by the' arrow g2, and these forces, operating at the opposite sides of the center L ofthe key-piece B, will impart a rotary movement to said.

inner face of the tension member A while the face e bore a corresponding relation to the inner face of .tension vmemberA so that, as soon as the key-piece commences to rotate, the edge z' is pressed against the inner face of member A as shown by arrow 2, while the edge z". is pressed against the inner face of member A as shown by arrow is. As a `result of the' co-action of these forces, which will be referredto'by the arrows, it will be apparent that both of the forces g2' and g3, serving to rotate the key-piece about its center 71,2, will set up the forces z'2 and 3. Itmay thus be said that the operation of pulling the tension members apart longitudinally produces forces g2 and g3 to rotate the key-piece while these forces set up forces 2 and 2 which serve topry said tensionmembers apart, z'. e., cause 'them to separatein a direction per-y pendicular to their adjacent faces.

In other words, they may be said to be a double bellcrank leverage arrangement, one bellcrank being considered as extending from the edge g to the center h and thence to the edge z",l while the other bellcrank theoretically extends from the edge g to the center 71, and thence to the edge z'. The work-arm of the first mentioned theoretical bellcrank may be'said to be an imaginary line gL and the power-arm hz", while the work-*arm of the other theoretical bellcrank is an imaginary line gh and the power-arm 105 is hz'. The work-arms of both these'theoretical bellcranks impart rotary movement to the key-piece, while their power-arms pry apart the tension members. This operationl continues from the very time that the solder 110 becomes soft enough to yield until the edges g and g slip oft' of the faces f and ff, whereupon there is nothing to further revstrain the-opposite ymovement of the tension' membersA and A,'and they slip longitudi- 115 nally of one yanother and are entirely re-l leased. 'i I The faces d2 and Z3 are, ineffect, abutments formed in the depressions or pockets of the tension members which are frequently known in the trade as tension plates while the faces e and e', /f and f constitute additional abutments on the key-piece. It will be apparent that the abutment cl2 cooperates with the abutment f of the key-piece, that the abutment Z3 cooperatesV with the abutment f of the key-piece, that the abutment e coperates with the inner face of the tension plate A, and that the abutment e cooperates with the inner face of tension plate A. `The 'abut'ments cl2 andI Z3 of the tension plates actingupon theabutments fand 7"V of thekey-piece transmitrotary movement .to the key-pieceand cause the abutments e. and eto operate. upon the inner vfaces of the tension members to forcibly. pry them apart..

..1 The vforegoingprying action ofthe ykeypiece .in releasing the parts of the-linksis, so'far as I am aware, .distinctly novel and produces very for-cible opening or disruption of the parts. lWIoreover, l-the distance to which the tension members need tobe forced 'apart is much less thanv has heretofore been the case with strut links, While the advantage of the stru-t links in having flat faces cofg operate Withionecanother to produce great strength and Withholding power as embodiedI in a: linkof :this invention.

Throughout the foregoing description theV structure shown in Figs. 1, 3 and 6 has been described as vthe preferred form of the invention, and,l in many cases, this form isv preferred. Howevergthestructure of the remainingv figures of the drawings possessV advantages over the said preferred form, .the

most striking of Which is thev` fact thatthe key-piece is entirely inclosed and* corrosion cannot set in at theedges of the link asy might be the case with the link of Fig.- 1, vif

said link werel improperly soldered. In the structure of `I" ig. 2' the key-piece is entirely'Y surrounded by solder and corrosion cannot possibly occur.

Having thus fully described the invention,`

What I claim as new, and desire to secure by Letters Patent, is.:

y 1. A fusible link embodying@ 'pair .of

lapped tension plates,each of which is provided-on its` inner face with afdepression or pocket, tapering in a directionflongitudi n-ally off the 'platetonfornn at the endE of each 'l pocket, an abutment extending transversely of the plate, said depressions or pockets-col# lectively forming a chamber when the plates arev in lapped relation, a key-piece:positioned in said chamber and provided with abut-v ments engaging With the abutments of the depressions or pockets, andl other abutments engaging with the inner faces of the plates,

fusible solder for uniting the parts, Where.

by, When*- the solder .is melted, v .the abutments of the depressions act upon the key-pieceA abutments which they engageA .to force the other abutments of the key-piece against the inner faces of the plates for the purpose offorcibly prying the plates apart..

' 2. A fusible link embodyingy a pair of lapped tension plates, each of which is provided vvith a transverse abutment, a keypiece provided with abutmentsvcooperating With'the abutments .of the tensionj plates and with shoulders .engaging with the inner faces of said plates, and fusible solder unit"- ing the Jparts,v whereby -When said solder is melted, the abutmen'ts .of the plates' act upon the abutments of the key-piece torotate-said key-piecev and'force the shoulders against theinnerfaces-of the plates. for the purpose of' forcibly separatingsaid' plates.-

3. A fusible lin-lr embodying a pair'fof Vlapped tension plates, each of which is pro-` vided vvithadepression forming. an abutment, said depressions collectively:forming a chamber to vhouse a key-piece when the plates are in lapped rel-atior'1,k a key-piece housed in said chamber, and fusible solder for uniting the parts, the a-butments of the tension plates coperating WithV the keypiece relatively adjacent the transverse aXis thereof to impart rotary movement thereto, when the .fusible solder is'melted, and. the keypiece also cooperating with thev tension plates relatively distant from` said transverse a-Xis to pry the plates lapart When the key-piece is rotated. Y

A fusible link embodying two-:comple-V mentary tension members, each of .which is provided with a shoulder,V a key-'piece provided With shoulders cooperating with the shoulders of the tension members,- and-With further shoulders engaging the adjacent faces, of lthe Ytensionv members and fusible solder for uniting the parts, whereby When the solder is melted, the lshoulders of thev tension membersrimpartrotary movement to the key-piece, causing theshoulders of the key-piece which engage Withthe adjacent.

ed; the abutments of the tensionplates actv upon the cooperating abutments of the keyi piece to impart rotarymovement to said key-piece and thereby cause the other. abuti-` ,ments'of the key-piece to pry` the tension plates apart. Y Y. Y.

In testimony :WhereoffI have signed myY name to this specification.Y

JAMES H. Menovvnnn vGopies offthsfpatent may belobtained forlve cents each, byiaddressng'the Commissioner ofkatents,

l WashingtonD.-VC.. 

